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Contributor II

Dramatic utilization reduction in 2.4GHz spectrum

Hi all,


Sometimes, as network admins and implementation engineers, we rarely get a visual representation of a configuration change that is aimed at improving performance.  We make the changes, check the config and wait to hear back from the user community. Rarely do we hear about improvements. We only hear back when things get worse. Sometimes we don't hear anything at all.


The opportunity to see a change's impact greatly increase when a customer has AirWave. I have a customer that has grown over the years and they gone from the very early days of AOS 2.5 and are currently running AOS 6.1. With their growth and AOS changes their configuration collected unwanted and unnoticed 'artifacts'. This is not an uncommon scenarior for many, time tested Aruba customers. Sometimes some pretty basic changes can be overlooked at older customers and small changes can be made to dramatically improve performance.


This particular customer still had the very low g-basic rates turned on all of their SSID's and still had some low g-tx-rates set. In an annual configuration audit, I spoke with them about turning off those rates as their 2.4 GHz utilization was quite high even in buildings that had very few active clients. They agreed to change and we implemented at 8am this morning. 


Here is the graphical representation of the utilization rates DRAMATICALLY decreasing. I don't get to see this too often and it makes my inner Airhead very, very happy to see. The radio represented is the 2.4GHz radio in an AP135. The AP is in an decades old brick and cinder block building full of classrooms. The deployment is bascially one ap every other classroom, and AP's are staggered to account for floors and hallways.


The new rates for the config are:


g-basic-rates 11 12

g-tx-rates 11 12 18 24 36 48 54





Small changes....big results!




Re: Dramatic utilization reduction in 2.4GHz spectrum

Thanks for sharing Brian....good stuff.

Systems Engineer, Northeast USA

Re: Dramatic utilization reduction in 2.4GHz spectrum

Excellent info!!!!

Really. thanks for sharing it with the community

Product Manager - Aruba Networks
Alternetworks Corp
Occasional Contributor II

Re: Dramatic utilization reduction in 2.4GHz spectrum

What version of Airwave is this? I do not see these graphs in my version 7.6.5. Thanks for sharing. 

Contributor II

Re: Dramatic utilization reduction in 2.4GHz spectrum

Sorry I didn't respond earlier.


It is version 7.7 but should be there in 7.6 as well. You do have to make sure that you have 'enabled' all the features in the Aruba OS to provide the statistics to the AirWave server. In particular, there is a command to send this type of information to the AMP:


mgmt-server type amp primary-server "ampIPaddress"


Of course, standard caveats apply when suggesting that you make config changes but this should start sending the data to your AMP server and graph tabs and associated graphs will show up shortly thereafter.




Contributor II

Re: Dramatic utilization reduction in 2.4GHz spectrum

By the way....setting the basic rates to 11 and 12 breaks the Nintendo WII


Unfortunately the only way to fix it was to create another AP-Group with a VAP / SSID combination that enabled the lower basic rates. We put the AP's nearest to the WII's into that group and the began working again.



Frequent Contributor II

Re: Dramatic utilization reduction in 2.4GHz spectrum



Can you advise what you would set the following to for both g and a rates to optimize (see attachment)



Re: Dramatic utilization reduction in 2.4GHz spectrum

Beautiful post. just awesome information.
Pasquale Monardo | Senior Network Solutions Consultant
ACDX #420 | ACCA
[If you found my post helpful, please give kudos!]
Frequent Contributor I

Re: Dramatic utilization reduction in 2.4GHz spectrum

Have you had any other issues in doing this besides the wii :)


Also how controlled is this environment as far as devices are concerned.  Is there any BYOD in place?  Are a majority of these devices issued and thus similar configurations or does it consist of a very diverse hardware/OS environment?





Contributor II

Re: Dramatic utilization reduction in 2.4GHz spectrum

I wouldn't touch the A rates as the 5GHz spectrum behaves much differently and in typically deployed environments little is gained by trimming the lower rates.


I've attached a screenshot of the rates that we are using in a typical "dorm / classroom" space with AP's in every other room.



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